Sizing / Hardening

[IanH]

I've switched over to gelatin/formalin for sizing my paper for gum printing - gel coat, dry, formalin soak, dry and repeat. I'm having much better results with this method than with gelatin/alum. Formalin is one of the few chemicals that really bothers me - one wiff and my eyes, nose and throat are on fire.
I got creative and tried using a plastic container in a method similar to drum-processing. So far, so good! I'm using a polyethylene wide mouthed container that protein-powder comes in. I curl the paper to the inside of the plastic container, add just a few ml of formalin sol'n, put the lid on, and swirl, rotate, roll etc., for a few minutes. NO Fumes and only a small amount of hardener solution is used.
Thought I'd pass this along in case anybody else wants to try this method.

[walter23]

Where do you get formalin? I'm just getting into gum printing and I am curious, in case I find I need to start sizing my own paper.

[IanH]

Where do you get formalin? I'm just getting into gum printing and I am curious, in case I find I need to start sizing my own paper.

Most chemical supplies firms carry formalin - around here it's Canadawide or Fisher Scientific. I was fortunate enough to get a small quantity of formalin from a veterinarian, rather than having to commit to purchasing a large quantity.

[walter23]

Just figured out that formalin is another name for formaldehyde. Thanks for the sizing tips; if I find I need to size the paper it'll be useful advice (not sure yet, but since so many people seem to do it for gum printing I figure it might be inevitable!).

[Colin Graham]

I was able to find foramlin locally in a pet supply store. It's used to control fish parasites. Avoid the product called Formalin 3- this is only 3% formalin and much too dilute. The solution I got is around 37% and was ~$30 per 500ml.

[IanH]

I'm wondering if anybody has tried some of the higher aldehydes like propanal (and beyond) as hardeners for gelatin. Formalin is working okay for me, but I am finding that it's action continues over a period of days, sometimes resulting in a rather brittle gelatin.

[Sidney]

I've switched over to gelatin/formalin for sizing my paper for gum printing - gel coat, dry, formalin soak, dry and repeat. I'm having much better results with this method than with gelatin/alum. Formalin is one of the few chemicals that really bothers me - one wiff and my eyes, nose and throat are on fire.
I got creative and tried using a plastic container in a method similar to drum-processing. So far, so good! I'm using a polyethylene wide mouthed container that protein-powder comes in. I curl the paper to the inside of the plastic container, add just a few ml of formalin sol'n, put the lid on, and swirl, rotate, roll etc., for a few minutes. NO Fumes and only a small amount of hardener solution is used.
Thought I'd pass this along in case anybody else wants to try this method.

Nice idea, but I don't really see an advantage in your technique.
I've tried hardening with formalin once in my bathroom, the vapors released during the drying process were reason enough for me to never do it again, inside.

Sidney

[IanH]

Nice idea, but I don't really see an advantage in your technique.
I've tried hardening with formalin once in my bathroom, the vapors released during the drying process were reason enough for me to never do it again, inside.

Sidney

When it's -20 degrees here, 'outside' work is not an option - inside with fume is the way to go - anything that reduces the amount of formalin is advantageous.

[Loris Medici]

Two options:

1. Try adding formalin into the gelatin solution and use it one shot. I usually prepare 100ml 3% gelatin solution and add 0.5ml formalin into it, keep the solution warm on a coffe cup heater, coat the papers and hang. That way, you'll finish the job in one step. When done, I pour the gelatin, wash the vessel and put 1:5 diluted bleach in it - which dissolves the non-washed remainder hardened gelatin completely. I coat 10-20 15x11" sheets and hang indoors, you can feel formaldehyde outgassing (if in a small room) but it's way more manageable than using a separate hardening bath. Just don't stay in that room and definitely use a room that can be ventilated with a transom window (vasistas/fortochka)...

2. Use Gamblin PVA size (or any other PVAc based bookbinding glue diluted to your liking; just look at the specs and make sure it's pH neutral, transparent, flexible and waterproof...). It's quick, and very effective.

Regards,
Loris.

[Colin Graham]

I've tried glutaraldehyde, which worked ok for gum, but I couldn't build up enough of a layer for carbon transfers and have it harden properly without yellowing. I also have used gyloxal quite a lot, but it's also has a tendency to yellow for some users.

Formalin works the best of everything I've tried, but I have a detached garage or probably couldn't use it. I got impatient over the weekend and brought some coated sheets into the darkroom to finish drying.. Even half-dry, the fumes gave me a headache that lasted for days.